Causes

The parasites that cause swimmer's itch live in the blood of waterfowl and in mammals that live near ponds and lakes. Examples include:

• Geese
• Ducks
• Gulls
• Beavers
• Muskrats

The parasite's eggs enter the water via their hosts' feces. Before infecting birds, other animals or people, the hatched parasites must live for a time within a type of snail. These snails live near the shoreline, which explains why infections occur most often in shallow water.

Swimmer's itch isn't contagious from person to person, so you don't need to worry about catching swimmer's itch from someone who has this itchy rash.